Sang, N. C., and N. C. Thang. “On the Design of an Optimum Active Mass-Spring-Inverted Pendulum Dynamic Vibration Absorber for the Inverted Pendulum Type Structure”. Vietnam Journal of Mechanics, vol. 30, no. 4, Dec. 2008, pp. 329 -, doi:10.15625/0866-7136/30/4/5638.